More than one-third of U.S. adults over 65 years of age have inadequate or marginal functional health literacy, and among indigent and minority patients in urban areas this number rises to over 80 percent. Face-to- face conversation with health providers remains one of the best methods for communicating health information to patients with low health literacy. The investigators have developed and successfully pilot tested a new computer agent technology for simulating face-to-face conversation with older adult patients in order to effect health education and behavior change in the area of physical activity promotion. In this research project the investigators will translate this pilot work into a computer system and protocol that can be readily deployed to ambulatory care settings, and will evaluate the efficacy of the resulting system as a mechanism to promote behavioral change among older adult patients with low health literacy in a two-arm randomized clinical trial. The intervention will be tailored for use primarily by an urban, African American, older adult population and evaluated in a similar study population. The computer agent intervention for walking promotion among older adults will occur in two-phases: (1) an intensive in-home, two-month, daily contact intervention deployed on a portable, touch-screen computer that patients carry home from the clinic, followed by (2) an occasional contact intervention via a kiosk-based computer that patients use when they come to their primary care clinic for an additional 10 months, to promote maintenance of walking behavior. The resulting intervention will be evaluated in a randomized study to assess its impact on walking behavior, fitness and mobility, and well-being in patients stratified by health literacy level, compared to a standard-of- care control condition. Older adults who begin an exercise program can reduce their risk of several chronic diseases (e.g., cardiovascular disease, type 2 diabetes, osteoporosis, etc.) as well as depression, disability, falls and overall mortality. Low health literacy has been associated with limitations in instrumental activities of daily living, activities of daily living, and limitations in activity because of physical health. The proposed study will determine whether a low-cost automated system that can be easily deployed from ambulatory clinics will be effective in motivating older adults with low literacy to obtain more physical activity.